Scheduling method and scheduling device for MBMS, and base station including this scheduling device

ABSTRACT

A scheduling method for multimedia broadcast/multicast service (MBMS) is provided according to the present invention, comprising steps of: configuring service specific information and service scheduling information separately from MBMS service data to form an MCCH control message of an MBMS control channel; and transmitting the MCCH control message and the MBMS service data to a receiving end, wherein the service specific information and the service scheduling information are applied with a single-frequency network combining scheme.

BACKGROUND OF THE INVENTION

1. Field of Invention

The present invention relates to mobile communication, and particularlyto a scheduling method and a scheduling device for MultimediaBroadcast/Multicast Service (MBMS), and a base station including thisscheduling device. In this manner, single frequency network (SFN)combining schemes are used for the service specific information and theservice scheduling information, and MBMS control channels (MCCH) areformed and multiplexed with data channels. Therefore, the system isimproved in robustness.

2. Description of Prior Art

3GPP (the Third Generation Partner Project) initiated a long-termevolvement (LTE) research project in 2005 to provide support foroperators' and user's increasing demands with higher data throughput andbetter network performance.

Multimedia Broadcast/Multicast Service (MBMS) is a service introduced by3GPP Rel6, which refers to a point-to-multipoint service through which adata source transmits data to multiple users. This service can thusachieve resource sharing of a network (including a core network and anaccess network) so as to serve as many multimedia users having the samedemands as possible by using least resources. In a radio access network,MBMS service can provide both message-oriented multicast and broadcastincluding plain text with a low rate, and multicast and broadcast ofmultimedia service with a higher rate, e. g., mobile phone TV, by usinga common transmission channel and a common radio bearer.

Currently, EMBMS (Evolved MBMS) is under various researches.

In prior art, the foremost control information, i.e., generalinformation for the MBMS, can not be combined. This results in extremelypoor robustness. Actually, some information, such as service specificinformation and service scheduling information, can be applied with asingle-frequency network (SFN) combining scheme. This is, however, notreflected in the prior art, which leads to a low efficiency. Moreover,multiplexing of control channels and data channels is not provided inthe prior art. It is to be noted that the multiplexing of the controlchannels and the data channels can reduce management complexity of theSFN area so that the data channels and the control channels can sharethe same resource allocation scheme and multi-cell coordination scheme.

SUMMARY OF THE INVENTION

The present invention is proposed to overcome the above problems.Therefore, it is an object of the present invention to provide ascheduling method and a scheduling device for multimediabroadcast/multicast service (MBMS), and a base station including thisscheduling device.

In this manner, the service specific information and the servicescheduling information are applied with a single-frequency networkcombining scheme, and MBMS control channels (MCCH) are formed andmultiplexed with data channels. Therefore, the system robustness isimproved.

To achieve the above object, according to the present invention, ascheduling method for multimedia broadcast/multicast service MBMS isprovided, comprising steps of: configuring service specific informationand service scheduling information separately from MBMS service data toform an MCCH control message of an MBMS control channel; andtransmitting the MCCH control message and the MBMS service data to areceiving end, wherein the service specific information and the servicescheduling information are applied with a single-frequency networkcombining scheme.

Preferably, the SFN combining scheme comprises SFN level combination,SFN area level combination and SFN area intersection level combination.

Preferably, the MCCH control message further comprises generalinformation which can be combined in SFN level.

Preferably, the general information comprises radio bearer RBconfiguration information, frequency information, timer information andtrigger information.

Preferably, the MCCH control message further comprises SFN area IDswhich are SFN area intersection level combinable.

Preferably, the MCCH control message further comprises cell specificinformation which includes a service list.

Preferably, the service list is SFN area intersection level combinable.

Preferably, the MCCH control message further comprises countinginformation which is cell level combinable for counting in on/offmanner.

Preferably, the service specific information and the service schedulinginformation which are applied with SFN area intersection levelcombination are added before all of the MBMS service data in ascheduling period.

Preferably, the service specific information and the service schedulinginformation which are applied with SFN area level combination is addedrespectively before each of the MBMS service data in a schedulingperiod.

Preferably, the MCCH control message is not based on reservation.

According to the present invention, a scheduling device for multimediabroadcast/multicast service MBMS is also provided, comprising: MCCHcontrol message forming means for configuring service specificinformation and service scheduling information separately from MBMSservice data to form an MCCH control message of an MBMS control channel;and transmission means for transmitting the MCCH control message and theMBMS service data to a receiving end, wherein the service specificinformation and the service scheduling information are applied with asingle-frequency network combining scheme.

Furthermore, according to the present invention, a base stationcomprising the above scheduling device is also provided.

According to the present invention, the control channel can be providedin SFN to the maximum extent so that capacity and reliability of thecontrol channel are improved.

The mobile station (UE) can reduce the time for reading the controlchannel so that battery life is prolonged.

BRIEF DESCRIPTION OF THE DRAWINGS

The above objects, advantages and features of the present invention willbecome apparent from a detailed description of preferred embodiments,taken below in conjunction with the accompanying figures, wherein:

FIG. 1 is a schematic diagram illustrating SFN area intersection levelcombination in the case that SFN areas intersect with each other;

FIG. 2 is a schematic diagram illustrating SFN area intersection levelcombination of the service specific information and the servicescheduling information in an MCCH control message according to thepresent invention;

FIG. 3 is a schematic diagram illustrating SFN area level combination ofthe service specific information and the service scheduling informationin the MCCH control message according to the present invention;

FIG. 4 is a flow diagram illustrating a scheduling method for MBMSservice according to the present invention; and

FIG. 5 is a block diagram illustrating a scheduling device for MBMSservice according to the present invention.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

In order to design MBMS control channel (MCCH) structure of the presentinvention, the following principles are considered:

1. performance at the edge of a cell;

2. the required bandwidth; and

3. battery saving for UE.

SFN operation or repetition (as used in 3GPP specification Release 6) isa method for effectively ensuring the performance at the edge of a cellfor a signaling message. However, this repetition (i. e., low codingrate) requires more bandwidth. According to the contents on MBMS in theRelease 6, 64 parallel MBMS services may exist simultaneously.Therefore, bit rate required for signaling transmission can exceed 100kbps. Consequently, the method according to the present invention canresult in higher transmission efficiency, i. e., larger channelcapacity.

On the other hand, the system capacity generated by using the SFNoperation will become much larger than that without the SFN operation.This would thus further reduce the bandwidth requirement. In the singlefrequency network, UE simultaneously receives the same wireless channelstransmitted from all of base stations and performs RF combination, whichis the so-called SFN operation. The SFN operation generates gain frommultiple-cell combination, allowing the system capacity to besignificantly increased. Larger system capacity means that the sameamount of data can be transmitted by using less bandwidth resource.

Furthermore, battery life is an important issue occurring in the MBMSservice. To save the battery life, the UE should be capable of readilyknow whether its concerned service exists. This is providedperiodically. Preferably, the signaling should be transmitted onlyduring very short time slot, and in most times, the UE disconnects thereceiver. From this point, the repetition method leads to longerrepletion time. The system capacity is significantly increased due touse of the SFN operation for MBMS signaling transmission so that thetime for transmitting the same amount of data is greatly reduced and thetime for UE to read this information is thereby reduced. Therefore, thebattery life is prolonged.

Therefore, the SFN operation should be used for the signaling message aswidely as possible.

Firstly, the composition of an MBMS control channel (MCCH) controlmessage will be discussed. According to the present invention, the MCCHcontrol message comprises the following six categories of information:

-   -   General information, e. g. radio bearer (RB) configuration        information, frequency information, timer information, trigger        information, etc.    -   Service specific information including notification/RB release,        etc. The notification information mainly notifies a user that        his concerned service has started or configurations have been        changed (including end of the service, RB release, etc.).    -   SFN area IDs (identifications). When the SFN operation is        performed, the information is transmitted in unit of the SFN        area. Each SFN area employs the same configuration and can be        easily indexed through IDs.    -   Service scheduling information for indicating which services        have been allocated with resources and which resources have been        allocated during a scheduling period.    -   Cell specific information including some information only        transmitted in the present cell, e.g., the information for        single-cell services, and also including a service list, etc.    -   Counting information for representing statistics for the number        of the UE that currently receive this service.

Among various information mentioned above, general information issignificant for all of the MBMS multi-cell transmission, which includesthe basic radio parameters, such as default RB configurationinformation, timer information, and trigger information. This generalinformation is common to all the cells in the SFN. Thus, the generalinformation could be SFN area wide combinable. It should be noted, suchgeneral information would be a considerable part of the MCCH controlmessage.

In general, the cell specific information can not be combined. But itshould be noted, for counting in on/off manner, the counting informationis cell common and thus cell level combinable.

Then, we will describe how to apply SFN combining schemes to the servicespecific information and the service scheduling information withreference to the figures.

Here, the SFN combining schemes includes SFN level combination, SFN arealevel combination and SFN area intersection level combination. The SFNlevel combination can be applied to any cells which support the SFNoperation. The SFN area level combination means that only signalstransmitted from the cells in the SFN area can be combined. The SFN areaintersection level combination means that different SFN areas coverdifferent areas, but those cells within the overlapping portions of theSFN areas have the same service data and the same control signaling, asa result of which, the signals transmitted from those cells arecombinable.

FIG. 1 is a schematic diagram illustrating SFN area intersection levelcombination in the case that SFN areas intersect with each other.

Two or more SFN areas may overlap with each other, as shown in FIG. 1.Every cell may belong to different SFN areas, but there may be someintersection part. Those cells in the SFN area intersection part in FIG.1 have the same information to be broadcasted for the service specificinformation and the service scheduling information. In such a case, theservice specific information and the service scheduling information canbe combined in SFN area intersection level. It should be noted that theSFN area intersection level combination is transparent to UE.

FIG. 2 is a schematic diagram illustrating the SFN area intersectionlevel combination of the service specific information and the servicescheduling information in an MCCH control message according to thepresent invention.

The service specific information and the service scheduling informationin the MCCH control message are configured separately from the MBMSservice data, as shown in FIG. 2. Here, the service specific informationand the service scheduling information are applied with the SFN areaintersection level combination.

The structure shown in FIG. 2 makes signaling notification easy. The UEmay have enough time to establish radio bearer (RB), because the servicespecific information and the service scheduling information can havesufficient time to be transmitted before the data transmission. The MTCH(MBMS transmission channel) in FIG. 2 is configured for transmitting theMBMS service data.

It should be noted that the structure of the MCCH control message inFIG. 2 is based on a non-reservation structure.

According to the present invention, MBMS data is transmitted based onthe SFN area intersection level combination of the service specificinformation and the service scheduling information in the MCCH controlmessage, as shown in FIG. 2. Therefore, during the scheduling period,the service specific information and the service scheduling informationare added the time domain before all of the MBMS service data to formthe MCCH control message of the present invention. The specific controlchannel structure is shown in FIG. 2.

For the scenario shown in FIG. 1, if most of the SFN areas areidentical, the gain from the SFN area intersection level combination asshown in FIG. 2 is similar to the SFN area level combination. In thescenario shown in FIG. 2, the service lists (the cell specificinformation) can also be combined in SFN area intersection level. Sincethe services of different SFN intersection parts are identical, theservice lists are bound to be the same and thus can be combined.

FIG. 3 is a schematic diagram illustrating the SFN area levelcombination of the service specific information and the servicescheduling information in the MCCH control message according to thepresent invention.

For all the cells in the same SFN area, The service specific informationand the service scheduling information in the MCCH control message areidentical. In such case, the service specific information and theservice scheduling information can be combined in SFN area level.

As shown in FIG. 3, during the scheduling period, the correspondingservice specific information and service scheduling information can beadded respectively before each of the MBMS service data, after thecorresponding service specific information and service schedulinginformation are combined in SFN area level.

It should be noted that the service specific information and the servicescheduling information can be transmitted on separate transmissionblocks (TB), so that they may have different QoS. For a plurality ofadjacent TBs on which the same MBMS service data is transmitted, theservice specific information and the service scheduling information areonly added in the first TB.

Such MCCH control message structure may have some drawback for signalingnotification. However, the service specific information and the servicescheduling information utilizes only a small amount of radio resources,so the MCCH and the MTCH (MBMS transmission channel) may be frequencydivision multiplexed (FDM).

The states of the MCCH control message applied with SFN combiningschemes according to the present invention have been shown above only asexamples. The present invention is not intended to be limited to this.

To sum up, with respect to the information in the MCCH control message,other than the service specific information and the service schedulinginformation:

-   -   the general information is SFN area level combinable;    -   the SFN area ID list can be combined in SFN area intersection        level;    -   the cell specific information for single-cell service generally        can not be combined, but the cell specific information for        multi-cell services (e. g., the service list) is SFN area        intersection level combinable; and    -   the counting information is generally cell-specific. For        counting in on/off manner, cell common counting is possible. In        such case, it can be combined in cell level.

As described above, according to the present invention, different typesof information in the MCCH control message can be combined in different(optimized) level.

FIG. 4 is a flow diagram illustrating a scheduling method for MBMSservice according to the present invention.

As shown in FIG. 4, at Step 401, the service specific information andthe service scheduling information are configured separately from theMBMS service data to form control message of MBMS control channel(MCCH). At Step 402, the MCCH control message and the MBMS service dataare then transmitted to a receiving end. Here, the service specificinformation and the service scheduling information are applied with asingle-frequency network (SFN) combining scheme. The SFN combiningscheme includes SFN level combination, SFN area level combination andSFN area intersection level combination. The specific application of thecombination schemes is described above.

FIG. 5 is a block diagram illustrating a scheduling device for MBMSservice according to the present invention. As shown in FIG. 5, thescheduling device according to the present invention comprises MCCH(MBMS control channel) control message forming means 501 andtransmission means 502. The MCCH control message forming means 501configures the service specific information and the service schedulinginformation separately from the MBMS service data to form the MCCHcontrol message. The transmission means 502 transmits the MCCH controlmessage and the MBMS service data to a receiving end. The servicespecific information and the service scheduling information are appliedin a single-frequency network combining scheme (SFN), as describedabove.

Here, the scheduling device can be included in a transmitting end of amobile communication system. This transmitting end is typically a basestation, and the receiving end described above is typically a mobilestation.

According to the present invention, the control channel can be providedin SFN to the maximum extent so that capacity and reliability of thecontrol channel are improved. The mobile station (UE) can reduce thetime for reading the control channel so that the battery life isprolonged.

Although the present invention has been shown in connection with thepreferred embodiments thereof, those skilled in the art will appreciatethat various modifications, substitutions and alternations can be madewithout departing the spirit and scope of the present invention.Therefore, the present invention should not be defined by the aboveembodiments but by the appended claims and equivalents thereof.

What is claimed is:
 1. A scheduling method for multimediabroadcast/multicast service (MBMS), comprising: configuring servicespecific information and service scheduling information separately fromMBMS service data to form an MBMS control channel (MCCH) control messageof an MBMS control channel; and transmitting the MCCH control messageand the MBMS service data to a receiving end, wherein the servicespecific information and the service scheduling information are appliedwith a single-frequency network (SFN) combining scheme and wherein theSFN combining scheme comprises SFN level combination, SFN area levelcombination and SFN area intersection level combination.
 2. The methodaccording to claim 1, wherein the MCCH control message further comprisesgeneral information which is SFN level combinable.
 3. The methodaccording to claim 2, wherein the general information comprises radiobearer RB configuration information, frequency information, timerinformation and trigger information.
 4. The method according to claim 1,wherein the MCCH control message further comprises SFN area IDs whichare SFN area intersection level combinable.
 5. The method according toclaim 1, wherein the MCCH control message further comprises cellspecific information which includes a service list.
 6. The methodaccording to claim 5, wherein the service list is SFN area intersectionlevel combinable.
 7. The method according to claim 1, wherein the MCCHcontrol message further comprises counting information which is celllevel combinable for counting in on/off manner.
 8. The method accordingto claim 1, wherein the service specific information and the servicescheduling information which are applied with SFN area intersectionlevel combination is added before all of the MBMS service data in ascheduling period.
 9. The method according to claim 1, wherein theservice specific information and the service scheduling informationwhich are applied with SFN area level combination is added respectivelybefore each of the MBMS service data in a scheduling period.
 10. Themethod according to claim 1, wherein the MCCH control message is notbased on reservation.
 11. A scheduling device for multimediabroadcast/multicast service (MBMS), comprising: an MBMS control channel(MCCH) control message processor for configuring service specificinformation and service scheduling information separately from MBMSservice data to form an MCCH control message of an MBMS control channel;and a transmitter for transmitting the MCCH control message and the MBMSservice data to a receiving end, wherein the service specificinformation and the service scheduling information are applied with asingle-frequency network (SFN) combining scheme and wherein the SFNcombining scheme comprises SFN level combination, SFN area levelcombination and SFN area intersection level combination.
 12. The deviceaccording to claim 11, wherein the MCCH control message furthercomprises general information which is SFN level combinable.
 13. Thedevice according to claim 12, wherein the general information comprisesradio bearer RB configuration information, frequency information, timerinformation and trigger information.
 14. The device according to claim11, wherein the MCCH control message further comprises SFN area IDswhich are SFN area intersection level combinable.
 15. The deviceaccording to claim 11, wherein the MCCH control message furthercomprises cell specific information which includes a service list. 16.The device according to claim 15, wherein the service list is SFN areaintersection level combinable.
 17. The device according to claim 11,wherein the MCCH control message further comprises counting informationwhich is cell level combinable for counting in on/off manner.
 18. Thedevice according to claim 11, wherein the scheduling device adds theservice specific information and the service scheduling informationwhich are applied with SFN area level combination are added before allof the MBMS service data in a scheduling period.
 19. The deviceaccording to claim 11, wherein the scheduling device adds the servicespecific information and the service scheduling information which areapplied with SFN area level combination is added respectively beforeeach of the MBMS service data in a scheduling period.
 20. The deviceaccording to claim 11, wherein the MCCH control message is not based onreservation.
 21. The device according to claim 11, implemented in a basestation.